Fluid droplet methodology and apparatus for imprint lithography

ABSTRACT

A method can be used to generate a fluid droplet pattern for an imprint lithography process using a fluid dispense system having fluid dispense ports. The method can include determining a fluid droplet pattern for dispensing a formable material onto a substrate; during a first pass, dispensing the formable material onto the substrate to form a first part of the fluid droplet pattern for an imprint field; offsetting the fluid dispense ports and substrate relative to each other in an offset direction; and during a second pass, dispensing the formable material onto the substrate to form a second part of the fluid droplet pattern for the imprint field. The method can be used to form a patterned layer over a semiconductor wafer in fabricating an electronic device. An apparatus can be configured to carry out the method.

FIELD OF THE DISCLOSURE

The present disclosure relates to imprint lithography, and more particularly to fluid droplet patterning for imprint lithography applications.

RELATED ART

Imprint lithography apparatuses and processes are useful in forming nanoscale patterns on semiconductor wafers in the fabrication of electronic devices. Such apparatuses and processes can include the use of fluid dispense systems for depositing a formable material, for example, a polymerizable material, such as a resin or a resist, onto the wafer, using techniques such as fluid droplet dispense. The dispensed material is contacted with an imprint template (or mold) having desired pattern features and then solidified, forming a patterned layer on the wafer. Template feature fill rates and related defects are dependent, in part, on template pattern feature density and orientation and the droplet pattern arrangement, including fluid droplet pitch.

Traditional fluid dispense systems permit some adjustment of inter-droplet spacing, however, they typically have constraints that limit the extent of such adjustments. The fluid dispense systems include fluid dispense ports having a fluid dispense port pitch that determines the fluid droplet pitch in the same direction as the fluid dispense port pitch. Thus, there continues to be an industry demand for droplet pattern processes which are more finely adjustable and which are not limited by dispenser limitations.

SUMMARY OF THE INVENTION

In an aspect, a method can be used to generate a fluid droplet pattern for an imprint lithography process. The method comprises:

providing a fluid dispense system having fluid dispense ports;

determining a fluid droplet pattern for dispensing a formable material onto a substrate;

during a first pass, dispensing the formable material onto the substrate to form a first part of the fluid droplet pattern for an imprint field, wherein the substrate and the fluid dispense ports move relative to each other in a translating direction;

offsetting the substrate and the fluid dispense ports relative to each other in the translating direction and another direction, wherein offsetting the substrate and the fluid dispense ports relative to each other is performed after dispensing the formable material during the first pass; and

during a second pass, dispensing the formable material onto the substrate to form a second part of the fluid droplet pattern for the imprint field, wherein dispensing the formable material during the second pass is performed after offsetting the substrate and the fluid dispense ports relative to each other.

In an embodiment, the translating direction and the other direction are substantially perpendicular to each other.

In another embodiment,

the fluid dispense ports define a line;

the fluid dispense system is configured to dispense fluid droplets of the formable material at a preset frequency to achieve spaced-apart droplets on the substrate at a preset minimum pitch as the substrate and the fluid dispense ports the substrate are moved relative to each other at a preset speed along a translating direction that is substantially perpendicular to the line; and

offsetting the substrate and the fluid dispense ports relative to each other in the translating direction is performed for a translating offset distance that is a non-integer multiple of the preset minimum pitch.

In a particular embodiment, during the first pass, the second pass, or each of the first and second passes, dispensing the formable material comprises dispensing the formable material such that the fluid droplet pitch in the translating direction is the preset minimum pitch or an integer multiple of the preset minimum pitch.

In a further embodiment, the fluid dispense ports have a fluid dispense port pitch; and offsetting the substrate and the fluid dispense ports relative to each other in the other direction is performed for another offset distance that is a non-integer multiple of the fluid dispense port pitch.

In still a further embodiment, during the second pass, a row of fluid droplets and a column of fluid droplets are formed.

In yet another embodiment, during the second pass, dispensing the formable material comprises dispensing the formable material such that centers of some of the fluid droplets lie along an X2 line of the drop edge exclusion (DEE) and centers of some other of the fluid droplets of the second pass lie along a Y2 line of the DEE.

In a particular embodiment, during the second pass, dispensing the formable material comprises dispensing the formable material such that none of the centers of the fluid droplets lie an X1 line or a Y1 line of the DEE.

In another embodiment, wherein during the first pass, dispensing the formable material comprises dispensing the formable material such that none of the centers of the fluid droplets lie an X2 line or a Y2 line of a DEE.

In a particular embodiment, wherein during the first pass, dispensing the formable material comprises dispensing the formable material such that centers of some of the fluid droplets lie along an X1 line of the DEE and centers of some other of the fluid droplets lie along a Y1 line of the DEE.

In a further embodiment, wherein after the first and second passes, at least one fluid droplet is at an intersection of X1 and Y1 lines of a DEE, or at least one other fluid droplet is at an intersection of X2 and Y2 lines of the DEE.

In another aspect, method can be used to manufacture an article. The method comprises:

providing a fluid dispense system having fluid dispense ports defining a line;

determining a fluid droplet pattern for dispensing a formable material onto a substrate;

during a first pass, dispensing the formable material onto the substrate to form a first part of the fluid droplet pattern for an imprint field, wherein the substrate and the fluid dispense ports move relative to each other in a translating direction;

offsetting the substrate and the fluid dispense ports relative to each other in the translating direction and another direction, wherein offsetting the substrate and the fluid dispense ports relative to each other is performed after dispensing the formable material during the first pass;

during a second pass, dispensing the formable material onto the substrate to form a second part of the fluid droplet pattern for the imprint field, wherein dispensing the formable material during the second pass is performed after offsetting the substrate and the fluid dispense ports relative to each other;

contacting the formable material with the template having a surface; and

curing the formable material to form a layer corresponding to the surface of the template.

In an embodiment, the article includes an electronic device, and the substrate includes a semiconductor wafer.

In a further aspect, an apparatus for imprint lithography comprises:

a fluid dispense system having fluid dispense ports;

a stage or the fluid dispensed ports adapted to move a substrate and the fluid dispense ports relative to each other; and

a logic element configured to:

-   -   determine a fluid droplet pattern for dispensing a formable         material onto a substrate;     -   transmit information to dispense the formable material onto the         substrate during a first pass to form a first part of the fluid         droplet pattern for an imprint field, wherein the substrate and         the fluid dispense ports move relative to each other in a         translating direction;     -   transmit information to offset the substrate and the fluid         dispense ports relative to each other in the translating         direction and another direction, wherein apparatus is configured         to offset the fluid dispense ports after an instruction to         dispense the formable material during the first pass is         executed; and     -   transmit information to dispense the formable material onto the         substrate during a second pass to form a second part of the         fluid droplet pattern for the imprint field, wherein apparatus         is configured to dispense the formable material during the         second pass after an instruction to offset the substrate and the         fluid dispense ports relative to each other is executed.

In an embodiment,

the fluid dispense ports lie along a line that is substantially perpendicular to the translating direction;

the fluid dispense system is configured to dispense fluid droplets of the formable material at a preset frequency to achieve spaced-apart droplets on the substrate at a preset minimum pitch as the substrate and the fluid dispense ports are moved relative to each other at a preset speed along the translating direction;

the information to dispense the formable material during the first pass, the second pass, or each of the first and second passes comprises particular information to dispense the formable material such that the fluid droplet pitch in the translating direction is the preset minimum pitch or an integer multiple of the preset minimum pitch; and

the information to offset the substrate and the fluid dispense ports relative to each other comprises particular information in which:

-   -   in the translating direction is performed for a translating         offset distance that is a non-integer multiple of the preset         minimum pitch; and     -   in the other direction is performed for another offset distance         that is a non-integer multiple of the fluid dispense port pitch.

In another embodiment, the information to dispense the formable material onto the substrate during the second pass comprises particular information such that centers of some of the fluid droplets lie along an X2 line of a DEE and centers of some other of the fluid droplets of the second pass lie along a Y2 line of the DEE.

In a particular embodiment, the information to dispense the formable material onto the substrate during the first pass comprises particular information such that centers of some of the fluid droplets lie along an X1 line of a DEE and centers of some other of the fluid droplets of the first pass lie along a Y1 line of the DEE.

In a more particular embodiment,

the information to dispense the formable material onto the substrate during the first pass comprises particular information such that such that none of the centers of the fluid droplets lie along the X2 line or the Y2 line of the DEE; and

the information to dispense the formable material onto the substrate during the second pass comprises particular information such that such that none of the centers of the fluid droplets lie along the X1 line or the Y1 line of the DEE.

In another embodiment, the information to dispense the formable material onto the substrate during the first and second passes includes information such to dispense the fluid droplets such that centers of fluid droplets closest to each of peripheral edges of the imprint field lie along X1, X2, Y1, and Y2 lines of a DEE.

In a further embodiment, the first part of the fluid droplet pattern is different from the second part of the fluid dispense pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated by way of example and are not limited in the accompanying figures.

FIG. 1 includes a fluid droplet pattern that matches the X-direction and Y-direction alignment for a drop edge exclusion.

FIG. 2 includes a fluid droplet pattern that does not match X-2 and Y-2 alignment for a drop edge exclusion.

FIG. 3 includes a simplified side view of an exemplary imprint lithography system.

FIG. 4 includes a simplified cross-sectional view of the substrate illustrated in FIG. 3, having a patterned layer.

FIG. 5 includes a simplified top view of a fluid dispense system including fluid dispense ports and an exemplary droplet pattern deposited upon a substrate surface.

FIG. 6 includes a flow chart of an exemplary method of forming an article, including generating a fluid droplet pattern.

FIG. 7 includes a simplified top view of a surface including part of a substrate fluid droplet pattern formed after a single pass in accordance with an embodiment.

FIG. 8 includes a simplified top view of the surface of FIG. 7 after forming another part of the substrate fluid droplet pattern during another pass in accordance with an embodiment.

FIG. 9 includes an illustration of the substrate and imprint lithography template during imprinting.

Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of embodiments of the invention.

DETAILED DESCRIPTION

The following description in combination with the figures is provided to assist in understanding the teachings disclosed herein. The following discussion will focus on specific implementations and embodiments of the teachings. This focus is provided to assist in describing the teachings and should not be interpreted as a limitation on the scope or applicability of the teachings.

The term “pitch” is intended to mean a distance from a center of a feature to a center of a next adjacent feature. For a fluid droplet pattern, the pitch is a distance from the center of a droplet to the center of the next adjacent droplet. In Cartesian coordinates, a two-dimensional pattern (a pattern as seen from a top or plan view) can have a pitch in the X-direction that corresponds to the distance between the centers of the features as measured in the X-direction (X-direction pitch), and a pitch in the Y-direction that corresponds to the distance between the centers of the features as measured in the Y-direction (Y-direction pitch). The X-direction pitch may be the same or different from the Y-direction pitch.

As used herein, speed and motion may be described on a relative basis. For example, object A and object B move relative to each other. Such terminology is intended to cover object A is moving, and object B is not; object A is not moving, and object B is moving; and both of objects A and B are moving.

As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having,” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of features is not necessarily limited only to those features but may include other features not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive-or and not to an exclusive-or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

The use of “a” or “an” is employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural, or vice versa, unless it is clear that it is meant otherwise.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The materials, methods, and examples are illustrative only and not intended to be limiting. To the extent not described herein, many details regarding specific materials and processing acts are conventional and may be found in textbooks and other sources within the imprint and lithography arts.

In imprint lithography, the formable material needs to be dispensed in a controlled matter to ensure that a proper amount of formable material is dispensed in correct locations and areal densities on the substrate. Centers of fluid droplets closest to the edges of the imprint field are placed such that, during an imprint operation, a proper amount of formable material can flow toward the edge of the imprint field. If the fluid droplets are too close to the edge, a portion of the formable material can flow beyond an edge of the imprint lithography template, and such portion of the formable material can result in an extrusion defect during a curing operation. The extrusion defect may adhere to the lithography template and cause the extrusion defect to be printed in the next imprint field. If the fluid droplets are too far from the edge, incomplete filling of template features may occur. Such defects are called “non-fill” defects and translate to a loss of features upon pattern transfer. Extrusion defects and non-fill defects are undesired

A drop edge exclusion (DEE) refers to an exclusion around a substrate fluid droplet pattern to achieve a proper amount of formable material near the edge of an imprint field that reduces the likelihood that (1) the formable material will flow beyond the edge of the imprint lithography template and (2) non-fill defects will occur. FIG. 1 illustrates an idealized substrate fluid drop pattern with proper DEE. The imprint field can be expressed in Cartesian coordinates along an X-direction and a Y-direction. The centers of fluid droplets along the column closest to the left-hand side lie along a line that is a distance X1 from the left-hand edge, and the centers of fluid droplets along the column closest to the right-hand side lie along a line that is a distance X2 from the left-hand edge. The centers of fluid droplets along the column closest to the bottom of the imprint field lie along a line that is a distance Y1 from the left-hand edge, and the centers of fluid droplets along the column closest to the top of the imprint field lie along a line that is a distance Y2 from the left-hand edge. Such lines are referred to herein as the X1 line, X2 line, Y1 line, and the Y2 line of the DEE. In FIG. 1, the fluid droplets have a uniform pitch in each of the X-direction and the Y-direction.

In actual practice, the proper DEE is difficult to obtain. FIG. 2 includes an illustration in which the substrate fluid droplet pattern has centers of fluid droplets along the X1 and Y1 lines but does not have centers of fluid droplets along the X2 and Y2 lines of the DEE. The substrate fluid droplet pattern in FIG. 2 has a significantly higher risk of non-fill defects along the top and right-hand edge of the imprint field as compared to FIG. 1. If an extra row or column were dispensed along the top or right-hand side of the imprint field at the same pitch in FIG. 2, then formable material would be too close to the edge of the imprint field. Such a substrate fluid droplet pattern has a significantly higher risk that formable material would flow beyond an edge of the lithographic imprint template and result in an extrusion defect.

With respect to the X-direction, a fluid dispense head (and the control software that operates it) has preset parameters (hereinafter “presets”) that can limit the flexibility of the fluid dispense system. The fluid dispense head has a preset firing frequency and a preset speed at which the fluid dispense head can move consistent with the presets. As used herein “the preset minimum pitch” is the distance between two immediately adjacent droplets dispensed at the preset firing frequency when the substrate and fluid dispense ports are moving relative to each other at the preset speed, which in the embodiment as illustrated in FIG. 3 is in the X-direction. The software control has difficulty with non-integer multiples of the preset minimum pitch. Accordingly, only a limited number of fluid droplet patterns that can be produced based on locations on a corresponding X-Y grid. Thus, the software control simply determines the closest integer of preset minimum pitch. However, the distance between the X1 and X2 lines in FIG. 2 may be a non-integer multiple of the preset minimum pitch. Consequently, the fluid dispense system forms a less-than ideal droplet pattern. With respect to the Y-direction, the fluid dispense ports and the substrate can be offset relative to each other between different passes of dispensing the formable material. This specification will briefly address the issues and solution to allow centers of fluid droplets to be dispensed along the X1, X2, Y1, and Y2 lines of the DEE.

Details regarding the apparatus and method are better understood after reading this specification in conjunction with figures. The description below is meant to illustrate embodiments and not limit the scope of the present invention, which is defined in the appended claims.

Referring to the figures, and particularly to FIG. 3, a lithographic system 10 in accordance with embodiments described herein can be used to form a relief pattern on a substrate 12. The substrate 12 may be coupled to a substrate chuck 14. As illustrated, substrate chuck 14 is a vacuum chuck; however, in other embodiments the substrate chuck 14 may be any chuck including vacuum, pin-type, groove-type, electrostatic, electromagnetic, or the like. Exemplary chucks are described in U.S. Pat. No. 6,873,087, which is hereby incorporated by reference in its entirety herein.

Substrate 12 and substrate chuck 14 may be further supported by a stage 16. The stage 16 may provide translating or rotational motion along the X-, Y-, or Z-directions. The stage 16, substrate 12, and substrate chuck 14 may also be positioned on a base (not illustrated).

Spaced-apart from the substrate 12 is a template 18. The template 18 can include a body having a first side and a second side with one side having a mesa 20 extending therefrom towards the substrate 12. The mesa 20 is sometimes referred to as a mold 20. In an embodiment, the template 18 can be formed without a mesa 20.

The template 18 or mold 20 may be formed from such materials including fused-silica, quartz, silicon, organic polymers, siloxane polymers, borosilicate glass, fluorocarbon polymers, metal, hardened sapphire, other similar materials, or any combination thereof. The template 18 and mold 20 can include a single piece construction. Alternatively, the template 18 and mold 20 can include separate components coupled together. As illustrated, a patterning surface 22 includes features defined by spaced-apart recesses 24 and protrusions 26. The disclosure is not intended to be limited to such configurations (e.g., planar surfaces). The patterning surface 22 may define any original pattern that forms the basis of a pattern to be formed on the substrate 12. In another embodiment, the patterning surface 22 can be a blank, that is, the patterning surface 22 does not have any recesses or projections.

The template 18 can be coupled to a chuck 28. The chuck 28 can be configured as vacuum, pin-type, groove-type, electrostatic, electromagnetic, or another similar chuck type. Exemplary chucks are further described in U.S. Pat. No. 6,873,087. In an embodiment, the chuck 28 may be coupled to an imprint head 30 such that the chuck 28 or imprint head 30 can facilitate movement of the template 18.

The lithographic system 10 can further include a fluid dispense system 32 used to deposit a formable material 34 on the substrate 12. For example, the formable material can include a polymerizable material, such as a resin. The formable material 34 can be positioned on the substrate 12 in one or more layers using techniques such as droplet dispense, spin-coating, dip coating, chemical vapor deposition (CVD), physical vapor deposition (PVD), thin film deposition, thick film deposition, or combinations thereof. The formable material 34 can be dispensed upon the substrate 12 before or after a desired volume is defined between the mold 20 and the substrate 12 depending on design considerations. For example, the formable material 34 can include a monomer mixture as described in U.S. Pat. No. 7,157,036 and U.S. Pat. No. 8,076,386, both of which are herein incorporated by reference in their entireties.

Referring to FIGS. 3 and 4, the lithographic system 10 can further include an energy source 38 coupled to a direct energy 40 along a path 42. The imprint head 30 and stage 16 can be configured to position the template 18 and substrate 12 in superimposition with the path 42. The lithographic system 10 can be regulated by a logic element 54 in communication with the stage 16, imprint head 30, fluid dispense system 32, or source 38, and may operate on a computer readable program, optionally stored in memory 56.

In an embodiment, either the imprint head 30, the stage 16, or both the imprint head 30 and the stage 16 vary a distance between the mold 20 and the substrate 12 to define a desired volume therebetween that is filled by the formable material 34. For example, the imprint head 30 can apply a force to the template 19 such that the mold 20 contacts the formable material 34 on the substrate 12. After the desired volume is filled with the formable material 34, the source 38 can produce energy 40, e.g., ultraviolet radiation, causing the formable material 34 to solidify or cross-link conforming to a shape of the surface 44 of the substrate 12 and patterning surface 22 defining a patterned layer 46 on the substrate 12. The patterned layer 46 can include features illustrated as protrusions 50 and recessions 52, with the protrusions 50 having a thickness, t₁ and the recessions 52 correspond to a residual layer having a thickness t₂, which is the residual layer thickness (RLT).

High throughput at low defect density is an important consideration in imprint lithography processes. When employing a droplet dispense method of applying the formable material to the substrate 12, the imprint process cycle generally includes (1) dispensing (or depositing) fluid droplets of formable material on a substrate surface, (2) bringing a template into contact with the fluid droplets such that the fluid spreads and fills the topography of the template patterning surface, (3) solidifying (e.g., photocuring) the fluid, and (4) separating the template from the substrate 12, leaving a solidified layer of formable material having a relief image of the template pattern on the substrate surface. Dispensing fluid droplets of formable material on the substrate surface and proper filling of the pattern of the template 18 are major contributors to the imprint cycle time, and thus throughput. Particular template patterns may require multiple passes of the substrate 12 relative to the imprint head 30. That is, the substrate 12 and imprint head 30 must be translated relative to each other multiple times. Multiple dispensing passes are common, for example, when templates have dense feature patterns or for particular patterns requiring adjacent droplets be positioned closer together. Methods and systems to reduce dispense time are described in accordance with one or more embodiments described herein.

During dispensing, fluid droplets of formable material are dispensed from the fluid dispense system 32 to create a pattern of fluid droplets on the substrate surface 44. The fluid droplet pattern can be determined such that the total volume of the fluid droplets on the surface matches the total volume for the desired fluid droplet pattern. As well as matching the total volume of the desired fluid droplet pattern, it may be desirable to match the local volume of the desired fluid droplet pattern. Thus, a greater volume of fluid can be dispensed in a region of the substrate 12 where a greater volume of formable material is desired.

Available inkjet systems can be tuned to dispense formable material fluid droplets with volumes in the range of 0.1 to 10 picoliters (pL) or greater, with 0.9 pL being an exemplary fluid droplet volume. The fluid droplets can be dispensed in patterns formed by one or more passes of the imprint head 30 and substrate 12 relative to one another. An exemplary pattern includes a rectangular, grid pattern, a diamond pattern, another suitable pattern, or any combination thereof.

Referring to FIG. 5, the fluid dispense system 32 can include fluid dispense ports 302. As illustrated, the fluid dispense system 32 includes six fluid dispense ports 302 a, 302 b, 302 c, 302 d, 302 e, and 302 f; however, the number of fluid dispense ports 302 can be less than or greater than six, such as for example, at least two fluid dispense ports, at least three fluid dispense ports, at least four fluid dispense ports, at least five fluid dispense ports, at least ten fluid dispense ports, or at least twenty fluid dispense ports. In an embodiment, the fluid dispense ports 302 can include a set of at least three fluid dispense ports (e.g., fluid dispense ports 302 a, 302 b, and 302 c) lying along a straight line 304. In traditional dispensing operations of formable material, a Y-direction pitch is fixed by a distance between centers of adjacent fluid dispense ports, and therefore, the Y-direction pitch is determined by the physical layout of the fluid dispense ports 302 in the fluid dispense head.

The fluid dispense system 32 and a surface 306 located there below (e.g., on the substrate 12 or the substrate chuck 14) can be moveable relative to each other in a translating direction (illustrated by arrow 308). Fluid droplets, including fluid droplets 310 a and 310 b, can be dispensed from the fluid dispense ports 302 onto the surface 306 in rows and columns.

As previously discussed, the fluid dispense head can have presets that can limit the flexibility of the fluid dispense system and produces a preset minimum pitch (X-direction pitch in the embodiment illustrated) when the substrate 12 is translated at a preset scan speed in the X-direction. The software control can determine the closest integer of preset minimum pitch. For example, a fluid dispense system may have a preset minimum pitch in the X-direction of 35 microns. Allowable integer values include 35 microns, 70 microns, 105 microns, etc. for the fluid droplet pitch in the X-direction.

The limitations on the fluid dispense port pitch and presets of the apparatus can allow a less-than ideal droplet pattern. An initial alignment of the substrate 12 and the fluid dispense ports 302 relative to each other allows the centers of the fluid droplets closest to the edges of the imprint field to lie along the X1 and Y1 lines of the DEE. A problem is obtaining centers of fluid droplets along the X2 and Y2 lines of the DEE.

In an embodiment, between passes in dispensing the formable material, the fluid dispense ports 302 can be offset in (1) the translating direction 308 for an translating offset distance and (2) another direction for another offset distance. In the embodiment as illustrated, the other offset direction can be substantially perpendicular to the translating direction 308, substantially parallel to the line 304, or both. In another embodiment, the other direction does not need to be substantially perpendicular to the translating direction 308.

As used herein, substantially perpendicular means ±10° of perpendicular, and substantially parallel means ±10° of parallel. The translating offset distance can be non-integer multiple of the preset minimum pitch, and the other offset distance can be non-integer multiple of the fluid dispense port pitch. The offset provides centers of fluid droplets along the X2 and Y2 lines of the DEE.

In accordance with an embodiment described herein, FIG. 6 includes a flow chart for a method that can be used forming a substrate fluid droplet pattern for an imprint lithography process that includes an offset between passes of dispensing the fluid droplets. The method can be performed by an imprint lithography apparatus including a fluid dispense system, a stage, and a logic element. In an embodiment, a fluid dispense system having fluid dispense ports 302 defining a line. The fluid dispense system can further be configured to dispense fluid droplets of a formable material at a preset frequency to achieve spaced-apart droplets on a substrate 12 at a preset minimum pitch or an integer multiple of the preset minimum pitch. The stage, the fluid dispense head, or both can be adapted to move relative to each other in a translating direction. The translating direction can be substantially parallel to the line. The logic element can include hardware, firmware, software, or any combination thereof to perform many of the operations described herein. In a particular embodiment, the logic element can be the processor 54. The substrate 12 can be placed on the stage, and in an embodiment, the substrate 12 can be a semiconductor wafer. p The method can include determining a fluid droplet pattern for dispensing the formable material onto the substrate, at block 602 in FIG. 6. In this particular embodiment, the formable material is dispensed using more than one pass. In a particular embodiment, the preset minimum pitch or an integer of the preset minimum pitch in the translating direction (X-direction) may allow centers of fluid droplets to be dispensed along the X1 and Y1 lines of the DEE.

The substrate 12 is placed and held onto the stage. The method can include, during a first pass, dispensing the formable material to form a first part of the fluid droplet pattern, at block 622. During the first pass, the substrate 12 and the fluid dispense ports 302 can move relative to each other in a translating direction at the preset speed. In a particular embodiment, the logic element can transmit information regarding the preset speed to the stage or a stage controller, to the fluid dispense head or a fluid dispense controller, or any combination thereof. FIG. 7 includes an illustration of an imprint field on the substrate after fluid droplets for the first pass have been dispensed. Centers of fluid droplets are along the X1 and Y1 lines of the DEE. In a particular embodiment, the center of a fluid droplet may lie at the intersection of the X1 and Y1 lines of the DEE.

However, as previously described and illustrated in FIG. 2, the presets can limit the ability to dispense in translating direction and dispense centers of fluid droplets on the X2 line of the DEE, and the fluid dispense port pitch can limit the ability to dispense centers of fluid droplets on the Y2 line of the DEE. None of the centers of fluid droplets lie along the X2 line or the Y2 line of the DEE.

At block 642, the method can further include offsetting the fluid dispense ports and substrate relative to each other after dispensing the formable material during the first pass. Offsetting will be in both the translating direction 308 and the other direction. The offset is to position the fluid dispense ports 302 to allow centers of fluid droplets to be dispensed along the X2 and Y2 lines of the DEE.

As an example, with respect to the translating direction 308 (X-direction), the preset minimum pitch may be 35 microns for the apparatus 10. A pitch of 40 microns may work best for a particular patterned layer to be achieved; however, 40 microns is 1.14 times 35 microns. Clearly, 1.14 is not an integer multiple of the preset minimum pitch of 35 microns. The prior example provides a tangible example and is not meant to limit the scope of the present invention. Other non-integer values for the preset minimum can be greater than 1.00, such as 1.01 X, 1.5 X, 2.1 X, 3.7 X, less than 1.00 and include 0.97 X, 0.86 X, 0.71 X, 0.57 X, 0.43 X, 0.29 X, 0.14 X, 0.03 X, or another non-integer value, where X represents the preset minimum pitch, and accordingly, the factor by which the preset speed is to be multiplied.

With respect to the other direction (Y-direction in the embodiment illustrated), the fluid dispense port pitch may be limited to constraints of the apparatus, such as the configuration of the fluid dispense head that holds the fluid dispense ports 302 in place. For example, the fluid dispense port pitch may be 25 microns. In this embodiment, the distance between the Y1 and Y2 lines of the DEE is not an integer multiple of the fluid dispense port pitch. To achieve centers of droplets along the Y2 line of the DEE, the fluid dispense port can be moved for an offset distance of 35 microns. Clearly, 35 microns is not an integer multiple of the fluid dispense port pitch of 25 microns. Accordingly, the substrate 12 and the fluid dispense ports 302 may be moved relative to each other in the Y-direction for a distance of 35 microns. The prior example provides a tangible example and is not meant to limit the scope of the present invention. Other non-integer values for the speed can be greater than 1.00, such as 1.01 Y, 1.5 Y, 2.1 Y, 3.7 Y, less than 1.00 and include 0.97 Y, 0.86 Y, 0.71 Y, 0.57 Y, 0.43 Y, 0.29 Y, 0.14 Y, 0.03 Y, or another non-integer value, where Y represents the fluid dispense port pitch, and accordingly, the factor by which the dispense port pitch is to be multiplied. The concepts described herein can apply to other dispense port pitches and corresponding offset distances.

Referring to the embodiment of FIG. 7, the offset is performed to move the substrate and the fluid dispense ports relative to each other in the translating direction (X-direction) for a distance that is a non-integer multiple of the preset minimum pitch and in the other direction (Y-direction) for a distance that is a non-integer multiple of the fluid dispense port pitch. For example, in reference to the fluid droplets along the right-most column in FIG. 7, the fluid dispense ports can be moved in the translating direction 308 (X-direction) 30 microns, which is non-integer multiple of 35 microns (the preset minimum pitch), and in the other direction (Y-direction) 40 microns, which is a non-integer of 25 microns (the fluid dispense port pitch). The particular values are only to provide a specific example and not to limit the scope of the present invention. In another embodiment, the offset may have other values, such as the best working pitch in either direction (such as 40 microns in the X-direction or 35 microns in the Y-direction). Still other values of the offset are possible provided the offset in any particular direction is a non-integer multiple of the pitch in view of how the apparatus is normally configured (for example, fluid dispense port pitch) and operates (for example, the preset minimum pitch).

The method can include, during a second pass, dispensing the formable material to form a second part of the fluid droplet pattern, at block 662. During the second pass, the substrate and the fluid dispense ports 302 can move relative to each other in a translating direction at the preset speed. In particular, the logic element can transmit information regarding the preset speed to the stage or a stage controller, to the fluid dispense head or a fluid dispense controller, or any combination thereof. FIG. 8 includes an illustration of an imprint field on the substrate with fluid droplets from the first and second passes. The centers of fluid droplets dispensed during the second pass are along the X2 and Y2 lines of the DEE. In a particular embodiment, a fluid droplet lies at the intersection of the X2 and Y2 lines of the DEE. None of the centers of fluid droplets from the second pass lie along the X1 or Y1 lines of the DEE.

At block 682, the method can include contacting the formable material with the template. In an embodiment, the template can have a patterned surface that has projections and recessions, and in another embodiment, the patterned surface can be a blank (a flat surface without any projections or recessions). FIG. 9 includes an illustration of portions of the substrate 12, formable material 34, and the mold 20. The left-hand portion illustrates the edge of the imprint field adjacent to the Y1 line of the DEE, and the right-hand portion illustrates the edge of the imprint field adjacent to the Y2 line of the DEE. The contact between the mold 20 of the template and the formable material 34 causes recessions in the mold 20 to fill and fill in the gaps between fluid droplets. The proper dispensing of fluid droplets allows some of the formable material to flow further from the Y1 and Y2 lines of the DEE and toward the edge of the imprint field; however, the formable material 34 does not flow beyond the edges of the mold 20. Gaps 101 and 102 between the edges of the formable material 34 and the mold 20 are controlled and kept relatively small so that non-fill defects will not occur and formable material 34 will not form extrusion defects.

At block 684, the method includes curing the formable material to form a patterned layer corresponding to the pattern surface of the template. Curing can be performed by exposure to electromagnetic radiation. In an embodiment, the electromagnetic radiation can be ultraviolet radiation. In another embodiment, the formable material can be cured using heat. The patterned layer on the substrate 12 has a complementary pattern as compared to the patterned surface of the template. Projections along the patterned layer correspond to recessions in the patterned surface of the template, and recessions in the patterned layer correspond to projections along the patterned surface of the template. The recessions in the patterned layer are parts of the residual layer.

A fluid dispense pattern can take many different shapes. An exemplary pattern includes a rectangular, grid pattern, a diamond pattern, another suitable pattern, or any combination thereof.

In a particular embodiment, the logic element may be the processor 54. The logic element may be split between different parts of the apparatus. For example, some operations of the logic element may be performed by the processor 54, and other operations of the logic element may be performed by stage controller, a fluid dispense head controller, or the like. Furthermore, information can be transmitted in order to carry out the actions described herein. The information can be in the form of instructions to be executed, signals, pulses, or the like. The stage 16, the fluid dispense system 32, or both may include a controller that can act on instructions received from the processor 54. In another embodiment, the stage 16, the fluid dispense system 32 may respond to analog signals received. For example, the information can be a particular direct current voltage or a light pulse. After reading this specification, skilled artisans will be able to configure an imprint lithography apparatus to meet the needs or desires in view of the equipment within the apparatus. Thus, the description of the embodiments does not limit the scope of the present invention.

After reading this specification, skilled artisans will appreciate that many other fluid drop patterns can be formed and still allow centers of fluid droplets to have centers along the X1, X2, Y1, and Y2 lines of the DEE. The offset of substrate 12 and the fluid droplet dispense ports 302 relative to each other can be performed without significantly affecting the ability to properly fill recessions in the template. Furthermore, more than two passes may be used to achieve fluid droplets along the X1, X2, Y1, and Y2 line of the DEE. After all passes are completed, the fluid droplet pattern will have centers of fluid droplets lying along the X1, X2, Y1, and Y2 lines of the DEE.

Patterned layers formed in accordance with embodiments herein have fewer defects as compared to corresponding patterned layers where dispensing formable material occurs without using the offset. More particularly, it has been found that patterned layers formed in accordance with embodiments herein have fewer defects as compared to corresponding patterned layers having rows and columns of fluid droplets closest to the edges of the imprint field such centers of such fluid droplets do not lie at the proper locations with respect as DEE. Without the offset, when centers of droplets closest to the edge of the imprint field are closer to the central region, insufficient formable material may be formed at the edge of the imprint field corresponding to the Y2 line, and non-fill defects are more likely. When centers of droplets closest to the edge of the imprint field are too close to the edge of the imprint field, formable material may flow beyond the edge of the template, and an extrusion defect is more likely. Thus, the offset allows for good filling characteristics and reduce the likelihood of non-fill and extrusion defects.

Note that not all of the activities described above in the general description or the examples are required, that a portion of a specific activity may not be required, and that one or more further activities may be performed in addition to those described. Still further, the order in which activities are listed is not necessarily the order in which they are performed.

Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.

The specification and illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The specification and illustrations are not intended to serve as an exhaustive and comprehensive description of all of the elements and features of apparatus and systems that use the structures or methods described herein. Separate embodiments may also be provided in combination in a single embodiment, and conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination. Further, reference to values stated in ranges includes each and every value within that range. Many other embodiments may be apparent to skilled artisans only after reading this specification. Other embodiments may be used and derived from the disclosure, such that a structural substitution, logical substitution, or another change may be made without departing from the scope of the disclosure. Accordingly, the disclosure is to be regarded as illustrative rather than restrictive. 

1. A method of generating a fluid droplet pattern for an imprint lithography process, the method comprising: during a first pass, dispensing a formable material onto a surface of a substrate by a fluid dispense system having fluid dispense ports to form a first fluid droplet pattern for a first part of an imprint field of the substrate, wherein the substrate and the fluid dispense ports move relative to each other along a translating axis; offsetting the substrate and the fluid dispense ports relative to each other, wherein offsetting is along a plane corresponding to the surface of the substrate in a direction along the translating axis and in another direction along the plane; and during a second pass, dispensing the formable material onto the surface of the substrate by the fluid dispense system to form a second fluid droplet pattern for a second part of the imprint field.
 2. The method of claim 1, wherein the translating direction and the other direction are substantially perpendicular to each other.
 3. The method of claim 1, wherein offsetting the substrate and the fluid dispense ports relative to each other is performed between the first and second passes.
 4. The method of claim 1, wherein during the first pass or the second pass: dispensing the formable material comprises dispensing fluid droplets of the formable material at a pitch along the translating axis, and offsetting is performed in the direction along the translating axis for a non-integer multiple of the pitch along the translating axis.
 5. The method of claim 4, wherein during the first pass or the second pass: dispensing the formable material comprises dispensing the fluid droplets of the formable material along a plurality of lines, wherein lines of the plurality of lines are spaced apart from one another at a pitch in the other direction, and offsetting is performed in the other direction for a non-integer multiple of the pitch in the other direction.
 6. The method of claim 1, wherein during the second pass, a row of fluid droplets and a column of fluid droplets are formed.
 7. The method of claim 1, wherein during the second pass, dispensing the formable material comprises dispensing the formable material such that centers of some of the fluid droplets lie along an X2 line of a drop edge exclusion and centers of some other of the fluid droplets of the second pass lie along a Y2 line of the drop edge exclusion.
 8. The method of claim 7, wherein during the second pass, dispensing the formable material comprises dispensing the formable material such that none of the centers of the fluid droplets lie along an X1 line or a Y1 line of the drop edge exclusion.
 9. The method of claim 1, wherein during the first pass, dispensing the formable material comprises dispensing the formable material such that none of the centers of the fluid droplets lie along an X2 line or a Y2 line of a drop edge exclusion.
 10. The method of claim 9, wherein during the first pass, dispensing the formable material comprises dispensing the formable material such that centers of some of the fluid droplets lie along an X1 line of the DEE and centers of some other of the fluid droplets lie along a Y1 line of the DEE.
 11. The method of claim 1, wherein after the first and second passes, at least one fluid droplet is at an intersection of X1 and Y1 lines of a drop edge exclusion, or at least one other fluid droplet is at an intersection of X2 and Y2 lines of the drop edge exclusion.
 12. A method of manufacturing an article, the method comprising: during a first pass, dispensing a formable material onto a surface of a substrate by a fluid dispense system having fluid dispense ports to form a first fluid droplet pattern for a first part of an imprint field of the substrate, wherein the substrate and the fluid dispense ports move relative to each other along a translating axis; offsetting the substrate and the fluid dispense ports relative to each other, wherein offsetting is along a plane corresponding to the surface of the substrate in a direction along the translating axis and in another direction along the plane; during a second pass, dispensing the formable material onto the surface of the substrate to form a second fluid droplet pattern for a second part of the imprint field; contacting the formable material with a template having a surface; and curing the formable material to form a layer corresponding to the surface of the template.
 13. The method of claim 12, wherein the article includes an electronic device, and the substrate includes a semiconductor wafer.
 14. An apparatus for imprint lithography comprising: a fluid dispense system having fluid dispense ports; a stage or the fluid dispensed ports adapted to move a substrate and the fluid dispense ports relative to each other; and a logic element configured to: transmit information to dispense a formable material onto a surface of a substrate during a first pass to form a first fluid droplet pattern for a first part of an imprint field of the substrate, wherein the substrate and the fluid dispense ports move relative to each other along a translating axis; transmit information to offset the substrate and the fluid dispense ports relative to each other, wherein the offset is along a plane corresponding to the surface of the substrate in a direction along the translating axis and in another direction along the plane; and transmit information to dispense the formable material onto the surface of the substrate during a second pass to form a second fluid droplet pattern for a second part of the imprint field.
 15. The apparatus of claim 14, wherein: the fluid dispense ports lie along a line that is substantially perpendicular to the translating direction; the fluid dispense system is configured to dispense fluid droplets of the formable material at a preset frequency to achieve spaced-apart droplets on the substrate at a preset minimum pitch as the substrate and the fluid dispense ports are moved relative to each other at a preset speed along the translating direction; the information to dispense the formable material during the first pass, the second pass, or each of the first and second passes comprises particular information to dispense the formable material such that the fluid droplet pitch in the translating direction is the preset minimum pitch or an integer multiple of the preset minimum pitch; and the information to offset the substrate and the fluid dispense ports relative to each other comprises particular information in which: in the translating direction is performed for a translating offset distance that is a non-integer multiple of the preset minimum pitch; and in the other direction is performed for another offset distance that is a non-integer multiple of the fluid dispense port pitch.
 16. The apparatus of claim 14, wherein the information to dispense the formable material onto the surface of the substrate during the second pass comprises particular information such that centers of some of the fluid droplets lie along an X2 line of a DEE and centers of some other of the fluid droplets of the second pass lie along a Y2 line of the DEE.
 17. The apparatus of claim 16, wherein the information to dispense the formable material onto the surface of the substrate during the first pass comprises particular information such that centers of some of the fluid droplets lie along an X1 line of a DEE and centers of some other of the fluid droplets of the first pass lie along a Y1 line of the DEE.
 18. The apparatus of claim 17, wherein: the information to dispense the formable material onto the surface of the substrate during the first pass comprises particular information such that such that none of the centers of the fluid droplets lie along the X2 line or the Y2 line of the DEE; and the information to dispense the formable material onto the surface of the substrate during the second pass comprises particular information such that such that none of the centers of the fluid droplets lie along the X1 line or the Y1 line of the DEE.
 19. The apparatus of claim 14, wherein: the information to dispense the formable material onto the surface of the substrate during the first pass comprises information to dispense fluid droplets of the formable material at a pitch along the translating axis, and the information to dispense the formable material onto the surface of the substrate during the second pass comprises information to dispense fluid droplets of the formable material along a plurality of lines, wherein lines of the plurality of lines are spaced apart from one another at a pitch in the other direction, and offsetting is performed in the direction along the translating axis for a non-integer multiple of the pitch along the translating axis and in the other direction for a non-integer multiple of the pitch in the other direction.
 20. The apparatus of claim 14, wherein the apparatus is configured to offset the fulid dispense ports between executing instructions to dispense the formable material during the first and passes. 